Dang Nguyen Hai Tran, 21, of San Jose, was driving a Toyota Camry involved in the crash, was arrested for suspicion of driving under the influence of marijuana, according to the California Highway Patrol.
Five others were taken to a hospital, including an infant. A juvenile remained in critical condition at the hospital.
The names of the victims have not been released.
The CHP says Dang Nguyen Hai Tran was reported to be speeding and driving recklessly before the crash.
"Driving under the influence, whether it's alcohol or drugs, the outcome is the same. It's dangerous. It kills people," said CHP Officer Manuel Leal.
All northbound lanes of I-880 were closed overnight for the investigation, but have since been reopened.